User's Manual

The RTU’s Jumpers
TYPE
PWM−Block
Static HI/LO
or MF/MV
PWM
f
rom uC
f
rom uC
Stage 1 Stage 2
from int.
Battery
J2=3−4
J2=1−2 or 1−3
J2=2−4
from external PS
"No Pullup"
"With Pullup, ext. PS"
"With Pullup, int. Batt"
1K
1K
DOUT
n
DOUT
n
DOUT
n
Fig. 16: Digital outputs
3.1.7 SDI-12 Interface
The SDI-12 interface is not available in the current A740 software version.
3.1.8 Expansion Port
The expansion port supports up to 3 addPORT expansion boxes. These have to be
connected using the expansion port cables supplied with the expansion box. The
position of the expansion box in this daisy chain determines its ID. The first
expansion box gets ID 1, the third expansion box in the chain gets ID 3.
Note: The cable used for the expansion port must not exceed 0.3 meters!
3.2 The RTU’s Jumpers
See below for the position of the various jumpers on the A740-board. Jumper J1 is
used for putting the system into programming mode for firmware updates and for
resetting the CPU. Jumper J2 is used to select the voltage source for the digital
outputs (see Section 3.1.6.). Jumpers J3 (DIGIN4) to J6 (DIGIN1) are used for
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